<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        .box{background-color: rgba(241, 63, 63, 0.534);
            width: 600px;
            height: 600px;

        }
        .d1{
            background-color: yellowgreen;
            width: 200px;
            height: 200px;
           
        }
        .d2{
            background-color: #f8669e;
            width: 200px;     
            height: 200px;      
        }
        .d3{
            background-color: #33fadf8a;
            width: 200px;
            height: 200px;
            margin: auto;
            overflow: hidden;         
        }
        .d4{
            background-color: #3be451;
            width: 100px;
            height: 100px;
            margin:30px auto;
            text-align: center;
            line-height: 100px;
        }
        .d5{
            background-color: rgb(224, 37, 37);
            width: 50px;
            height: 50px;
            text-align: center;
            line-height: 50px;
        }
        .d6{
            background-color: rgb(238, 182, 99);
            width: 50px;
            height: 50px;
            text-align: center;
            line-height: 50px;
        }
    </style>
</head>
<body>
    <div class="box">
        <div class="d1">
            1
        </div>
        <div class="d2">
            <div class="d5">
                6
            </div>
            <div class="d6">
                66
            </div>
        </div>
        <div class="d3">
            
            <div class="d4">
                666
            </div>
        </div>
    </div>
</body>
</html>